This 5.1 MHz circuit was found in a 1980s documentation. The frequency is given by the crystal and general purpose transistors can be used.
The resistors in this circuit marked with * must be within 1% tolerance. The circuit is from the...
This amplifier with very high input resistance has variable gain and must be powered by a...
This regulator is equivalent to 2 AA batteries providing a 5 V output voltage. The circuit is from...